Air circuit breakers as described within U.S. Pat. No. 3,095,489 entitled "Manual Charging Means for Stored Energy Closing Mechanisms of Electric Circuit Breakers" and U.S. Pat. No. 3,084,238 entitled "Ratchet Mechanism for Charging a Closing Spring in an Electric Circuit Breaker" include operating mechanisms that are mainly exposed to the environment. Since the air circuit breakers are rated to carry several thousand amperes of current continuously, the exposure to convection cooling air assists in keeping the operating components within reasonable temperature limits.
U.S. patent application Ser. No. 08/878,598 entitled "Contact Position Indicator for an Industrial-Rated Circuit Breaker", filed concurrently herewith, describes the use of a target device to indicate the condition of the circuit breaker contacts as well as an interlock arrangement for preventing false indication thereof.
Various accessory devices are used with such air circuit breakers to provide auxiliary function along with overcurrent protection. One such accessory is the bell alarm accessory that provides local and remote indication as to the occurrence of circuit interruption. U.S. Pat. No. 5,502,286 entitled "Bell Alarm and Lock-Out for High Ampere-Rated Circuit Breakers" describes a bell alarm accessory used with so-called "insulated case" circuit breakers wherein the circuit breaker interrupting components are completely enclosed within an insulating plastic enclosure. This patent describes one such bell alarm accessory that interacts with the circuit breaker operating mechanism to activate the bell alarm upon circuit interruption and to prevent the closing of the circuit breaker contacts until the accessory is manually reset.
It would be beneficial to provide a similar bell alarm with air circuit breakers to indicate the occurrence of a circuit interruption and to prevent the closing of the circuit breaker contacts until the accessory is manually reset.
One purpose of the instant invention is to provide a bell alarm accessory that provides local as well as remote indication of such circuit interruption as well as preventing circuit breaker contact closure until and unless the accessory has become manually reset.